Ceramic Crucible: a Hessian Crucible of Equal Weights of Clay and Sand (Thorpe 1912)

A ceramic crucible is a fired clay pot for melting metal. Thorpe's Dictionary of Applied Chemistry (1912) describes the Hessian crucible: equal weights of clay and sand, usually triangular, coarse and porous; it withstands a very high heat but cracks on sudden changes of temperature and is quickly eaten by litharge. His general rules for clay crucibles fill in the work: weather the clay, beat it fine to drive out air, mix in the sand, form the crucibles and bake small ones in a kiln. Sizes, forming and baking heat are not given. Source: Thorpe, Dictionary of Applied Chemistry vol. II (1912), CRUCIBLES, pp. 168-169. Picture: the Hessian paragraph.